1. Field of the Invention
The present invention relates to a structure of a light source device using a discharge lamp and a structure of a projection type display device on which the light source device is mounted.
2. Description of the Background Art
As a light emitting source of a light source device to be mounted on a projection type display device such as a liquid crystal projector, a discharge lamp such as a high pressure mercury-vapor lamp or a metal halide lamp has often been used. Since the discharge lamp of this kind has a very high internal pressure during lighting, it rarely bursts during lighting. There is a danger if the discharge lamp bursts and a fragment thereof is thereby scattered to the outside of a light source device or the outside of a projection type display device. Therefore, a fragment scattering prevention structure has conventionally been introduced into the light source device.
FIG. 19 is a perspective view showing an external structure of a conventional light source device, FIG. 20 is a sectional view showing a sectional structure taken along a virtual plane A in FIG. 19, and FIG. 21 is a sectional view showing a sectional structure taken along a virtual plane B in FIG. 19 (see Japanese Patent Application Laid-Open No. 10-223023 (1998)). In FIGS. 19 to 21, the reference numeral 1 denotes a discharge lamp, the reference numeral 2 denotes a base, the reference numeral 3 denotes a feeder, the reference numeral 4 denotes a concave reflecting mirror, the reference numeral 5 denotes a front plate formed of a translucent material, the reference numeral 6 denotes a sleeve, the reference numeral 7 denotes an adhesive, the reference numeral 8 denotes a wire net, the reference numeral 9 denotes a cervical portion, the reference numerals 100 to 102 denote vent holes, the reference numeral 10 denotes a whole light source device, and a line C1-C2 denotes a center of an optical axis.
Next, description will be given to the structure and operation of the light source device 10. The discharge lamp 1 fixed to the base 2 is inserted in the cervical portion 9 of the concave reflecting mirror 4. The base 2 is fixed to the sleeve 6 with the adhesive 7. The sleeve 6 is fixed to the concave reflecting mirror 4 with the adhesive 7 after the optical axis C1-C2 is adjusted. The front plate 5 to be a light emitting surface is bonded and fixed to an opening on the light emitting side of the concave reflecting mirror 4. A container surrounding the discharge lamp 1 is constituted by the concave reflecting mirror 4 and the front plate 5. The vent hole 100 is formed on a peripheral edge of the opening on the light emitting side of the concave reflecting mirror 4 (see FIG. 20), and the wire net 8 is provided over the vent hole 100. While the vent hole is provided in four places of the concave reflecting mirror in the Japanese Patent Application Laid-Open No. 10-223023 (1998), the vent hole in only one place is shown for simplicity of the drawing.
A partial nick is provided on the sleeve 6, thereby forming the vent holes 101 and 102. Cooling air is introduced and discharged through the vent holes 100 to 102 between an internal space of the light source device 10 (an internal space of the container constituted by the concave reflecting mirror 4 and the front plate 5) and an external space so that the discharge lamp 1 is cooled down.
In the case in which the discharge lamp 1 bursts during lighting, a fragment thereof is enclosed in the light source device 10 by means of the front plate 5 and the wire net 8 provided over the vent hole 100. Such a structure has widely been applied to a current main light source device such as a projection type display device.
FIG. 22 is a perspective view showing an external structure of a conventional projection type display device, FIG. 23 is a front view showing a structure of an axial flow fan mounted on the conventional projection type display device, and FIG. 24 is a perspective view showing an internal structure of the conventional projection type display device. In FIG. 22, the reference numeral 501 denotes a projection lens, the reference numeral 502 denotes an operation panel, the reference numeral 504 denotes an axial flow fan, the reference numeral 510 denotes a projecting luminous flux and the reference numeral 500 denotes a whole projection type display device. In FIG. 23, moreover, the reference numeral 506 denotes a fan case, the reference numeral 507 denotes a rotation axis of a wing, the reference numerals 504a and 504b denote fan wings which are adjacent to each other, and the reference numeral 504 denotes the whole axial flow fan. In FIG. 24, furthermore, the reference numeral 519 denotes an optical synthesizing prism, the reference numeral 520 denotes a power supply device, the reference numeral 521 denotes a cooling fan, the reference numeral 522 denotes an electronic circuit board, the reference numeral 523 denotes an optical system, the reference numeral 524 denotes a light bulb, and the reference numeral 525 denotes a light source device housing. In FIG. 24, the same reference numerals as those in FIG. 22 denote the same or corresponding portions.
Next, an operation will be described with reference to FIGS. 22 and 24. When a power switch provided on the operation panel 502 is turned ON, a discharge lamp of a light source device provided in the light source device housing 525 is lighted up. A light emitted from the discharge lamp is controlled by the optical system 523 so that the light bulb 524 representing an image to be displayed is illuminated. The image formed by the light bulb 524 is synthesized by the optical synthesizing prism 519 and is changed into the projecting luminous flux 510 by means of the projection lens 501, and is thus projected onto a display surface such as a screen. When the discharge lamp is lighted up, the axial flow fan 504 is operated for cooling the discharge lamp. When the axial flow fan 504 has such a wing structure that a great clearance 504ab is provided between the wings 504a and 504b adjacent to each other in an orthogonal projected image obtained by orthogonal projection in a direction of the rotation axis 507 of the wing (a perpendicular direction to the paper) (when the wing is projected onto a projecting surface perpendicular to the rotation axis 507 by parallel rays with the rotation axis 507 of the wing).
The conventional light source device 10 has the above-mentioned structure. For this reason, there is a problem in that a smaller fragment than a dimension of meshes of the wire net 8 or a smaller fragment than a clearance provided between the discharge lamp 1 and an internal surface of the cervical portion 9 is scattered to the outside of the light source device 10 at a wind pressure applied at time of a burst and cannot be completely enclosed in the light source device 10.
Moreover, since the conventional projection type display device 500 has the above-mentioned structure, there is a problem in that a fragment coming out of the light source device easily passes through the clearance 504ab between the wings of the fan 504 toward the outside when the discharge lamp bursts during lighting for some reason.
It is an object of the present invention to provide a light source device and a projection type display device which can completely enclose a fragment therein even if a discharge lamp bursts during lighting.
A first aspect of the present invention is directed to a light source device comprising a discharge lamp, a container, a first vent hole and a cutoff mechanism. The container is provided to surround the discharge lamp and partially has a translucent light emitting surface. The first vent hole is provided in the container. The cutoff mechanism has a movable member for being pressed by a pressure wave applied from an internal space of the container to cut off a spatial connection of the internal space and an external space through the first vent hole, and is provided in the vicinity of the first vent hole.
When the discharge lamp bursts, the movable member of the cutoff mechanism is pressed by the pressure wave generated at time of the burst so that the spatial connection between the internal space of the container and the external space is cut off. Consequently, it is possible to prevent a fragment of the discharge lamp from being scattered to the external space of the container.
A second aspect of the present invention is directed to a light source device comprising a discharge lamp, a concave reflecting mirror, a fixing member, a box member and a movable member. The concave reflecting mirror is disposed with the discharge lamp provided therein. The fixing member has a first vent hole to be spatially connected to an internal space of the concave reflecting mirror and serves to position and fix the discharge lamp and the concave reflecting mirror to each other. The box member has a second vent hole to be spatially connected to the first vent hole and is disposed with the fixing member provided therein. The movable member is provided in the box member in the vicinity of the second vent hole and is pressed by a pressure wave applied from the internal space, thereby cutting off a spatial connection of the internal space and an external space of the box member through the first and second vent holes.
When the discharge lamp bursts, the movable member is pressed by the pressure wave generated at time of the burst to close the second vent hole. Consequently, the spatial connection between the internal space of the concave reflecting mirror and the external space of the box member is cut off. Accordingly, it is possible to prevent a fragment of the discharge lamp from being scattered to the external space.
A third aspect of the present invention is directed to a projection type display device comprising a light source device, a light bulb, an optical system and a projection lens. The light bulb represents an image to be displayed. The optical system irradiates a light emitted from the light source device on the light bulb. The projection lens projects, onto a display surface, the image of the light bulb on which the light is irradiated. The light source device includes a discharge lamp, a container, a first vent hole and a cutoff mechanism. The container is provided to surround the discharge lamp and partially has a translucent light emitting surface. The first vent hole is provided in the container. The cutoff mechanism has a movable member for being pressed by a pressure wave applied from an internal space of the container to cut off a spatial connection of the internal space and an external space through the first vent hole, and is provided in the vicinity of the first vent hole.
It is possible to prevent a fragment of the discharge lamp provided in the light source device from being scattered to the external space of the projection type display device when the same discharge lamp bursts.
A fourth aspect of the present invention is directed to a projection type display device comprising a light source device, a light bulb, an optical system and a projection lens. The light bulb represents an image to be displayed. The optical system irradiates a light emitted from the light source device on the light bulb. The projection lens projects, onto a display surface, the image of the light bulb on which the light is irradiated. The light source device includes a discharge lamp, a concave reflecting mirror, a fixing member, a box member and a movable member. The concave reflecting mirror is disposed with the discharge lamp provided therein. The fixing member has a first vent hole to be spatially connected to an internal space of the concave reflecting mirror and serves to position and fix the discharge lamp and the concave reflecting mirror to each other. The box member has a second vent hole to be spatially connected to the first vent hole and is disposed with the fixing member provided therein. The movable member is provided in the box member in the vicinity of the second vent hole and is pressed by a pressure wave applied from the internal space, thereby cutting off a spatial connection of the internal space and an external space of the box member through the first and second vent holes.
It is possible to prevent a fragment of the discharge lamp provided in the light source device from being scattered to the external space of the projection type display device when the same discharge lamp bursts.
A fifth aspect of the present invention is directed to a projection type display device comprising a light source device, a light bulb, an optical system, a projection lens, a housing and an axial flow fan. The light source device has a discharge lamp. The light bulb represents an image to be displayed. The optical system irradiates a light emitted from the light source device on the light bulb. The projection lens projects, onto a display surface, the image of the light bulb on which the light is irradiated. The housing accommodates at least the light source device therein. The axial flow fan is provided in the housing and has a plurality of wings arranged around a rotation axis. The axial flow fan has such a wing configuration that a clearance is not provided between the wings which are adjacent to each other in an orthogonal projected image obtained by orthogonal projection in a direction of the rotation axis.
The axial flow fan has such a wing configuration that a clearance is not provided between the wings which are adjacent to each other in an orthogonal projected image. Even if a fragment of the discharge lamp provided in the light source device comes out of the light source device when the same discharge lamp bursts, therefore, it is possible to prevent the fragment from being scattered from the axial flow fan to an external space of the projection type display device.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.